NEWS
author wenzelm
Sat Nov 24 16:53:31 2001 +0100 (2001-11-24)
changeset 12280 fc7e3f01bc40
parent 12253 1886dc96b7e9
child 12312 f0f06950820d
permissions -rw-r--r--
tuned;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle2001 (?? 2001)
     6 -----------------------------
     7 
     8 *** Document preparation ***
     9 
    10 * greatly simplified document preparation setup, including more
    11 graceful interpretation of isatool usedir -i/-d/-D options, and more
    12 instructive isatool mkdir; users should basically be able to get
    13 started with "isatool mkdir Test && isatool make";
    14 
    15 * theory dependency graph may now be incorporated into documents;
    16 isatool usedir -g true will produce session_graph.eps/.pdf for use
    17 with \includegraphics of LaTeX;
    18 
    19 * proper spacing of consecutive markup elements, especially text
    20 blocks after section headings;
    21 
    22 * support bold style (for single symbols only), input syntax is like
    23 this: "\<^bold>\<alpha>" or "\<^bold>A";
    24 
    25 * \<bullet> is now output as bold \cdot by default, which looks much
    26 better in printed text;
    27 
    28 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    29 note that these symbols are currently unavailable in Proof General /
    30 X-Symbol;
    31 
    32 
    33 *** Isar ***
    34 
    35 * improved proof by cases and induction:
    36   - 'case' command admits impromptu naming of parameters (such as
    37     "case (Suc n)");
    38   - 'induct' method divinates rule instantiation from the inductive
    39     claim; no longer requires excessive ?P bindings for proper
    40     instantiation of cases;
    41   - 'induct' method properly enumerates all possibilities of set/type
    42     rules; as a consequence facts may be also passed through *type*
    43     rules without further ado;
    44   - 'induct' method now derives symbolic cases from the *rulified*
    45     rule (before it used to rulify cases stemming from the internal
    46     atomized version); this means that the context of a non-atomic
    47     statement becomes is included in the hypothesis, avoiding the
    48     slightly cumbersome show "PROP ?case" form;
    49   - 'induct' may now use elim-style induction rules without chaining
    50     facts, using ``missing'' premises from the goal state; this allows
    51     rules stemming from inductive sets to be applied in unstructured
    52     scripts, while still benefitting from proper handling of non-atomic
    53     statements; NB: major inductive premises need to be put first, all
    54     the rest of the goal is passed through the induction;
    55   - 'induct' proper support for mutual induction involving non-atomic
    56     rule statements (uses the new concept of simultaneous goals, see
    57     below);
    58   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    59   - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
    60   - moved induct/cases attributes to Pure, methods to Provers;
    61   - generic method setup instantiated for FOL and HOL;
    62 
    63 * Pure: support multiple simultaneous goal statements, for example
    64 "have a: A and b: B" (same for 'theorem' etc.); being a pure
    65 meta-level mechanism, this acts as if several individual goals had
    66 been stated separately; in particular common proof methods need to be
    67 repeated in order to cover all claims; note that a single elimination
    68 step is *not* sufficient to establish the two conjunctions, so this
    69 fails:
    70 
    71   assume "A & B" then have A and B ..   (*".." fails*)
    72 
    73 better use "obtain" in situations as above; alternative refer to
    74 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
    75 
    76 * Pure: proper integration with ``locales''; unlike the original
    77 version by Florian Kammüller, Isar locales package high-level proof
    78 contexts rather than raw logical ones (e.g. we admit to include
    79 attributes everywhere); operations on locales include merge and
    80 rename; e.g. see HOL/ex/Locales.thy;
    81 
    82 * Pure: theory goals now support ad-hoc contexts, which are discharged
    83 in the result, as in ``lemma (assumes A and B) K: A .''; syntax
    84 coincides with that of a locale body;
    85 
    86 * Pure: renamed "antecedent" case to "rule_context";
    87 
    88 * Pure: added 'corollary' command;
    89 
    90 * Pure: fixed 'token_translation' command;
    91 
    92 * Pure: removed obsolete 'exported' attribute;
    93 
    94 * Pure: dummy pattern "_" in is/let is now automatically lifted over
    95 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
    96 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
    97 
    98 * Pure: method 'atomize' presents local goal premises as object-level
    99 statements (atomic meta-level propositions); setup controlled via
   100 rewrite rules declarations of 'atomize' attribute; example
   101 application: 'induct' method with proper rule statements in improper
   102 proof *scripts*;
   103 
   104 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   105 now consider the syntactic context of assumptions, giving a better
   106 chance to get type-inference of the arguments right (this is
   107 especially important for locales);
   108 
   109 * Provers: 'simplified' attribute may refer to explicit rules instead
   110 of full simplifier context; 'iff' attribute handles conditional rules;
   111 
   112 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   113 
   114 * HOL: 'recdef' now fails on unfinished automated proofs, use
   115 "(permissive)" option to recover old behavior;
   116 
   117 * HOL: 'inductive' no longer features separate (collective) attributes
   118 for 'intros' (was found too confusing);
   119 
   120 * HOLCF: domain package adapted to new-style theories, e.g. see
   121 HOLCF/ex/Dnat.thy;
   122 
   123 * ZF: proper integration of logic-specific tools and packages,
   124 including theory commands '(co)inductive', '(co)datatype',
   125 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   126 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   127 
   128 
   129 
   130 *** HOL ***
   131 
   132 * HOL: moved over to sane numeral syntax; the new policy is as
   133 follows:
   134 
   135   - 0 and 1 are polymorphic constants, which are defined on any
   136   numeric type (nat, int, real etc.);
   137 
   138   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   139   binary representation internally;
   140 
   141   - type nat has special constructor Suc, and generally prefers Suc 0
   142   over 1::nat and Suc (Suc 0) over 2::nat;
   143 
   144 This change may cause significant INCOMPATIBILITIES; here are some
   145 hints on converting existing sources:
   146 
   147   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   148   entities, so expressions involving "-" (unary or binary minus) need
   149   to be spaced properly;
   150 
   151   - existing occurrences of "1" may need to be constraint "1::nat" or
   152   even replaced by Suc 0; similar for old "2";
   153 
   154   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   155 
   156   - remove all special provisions on numerals in proofs;
   157 
   158 * HOL/record package improvements:
   159   - new derived operations "fields" to build a partial record section,
   160     "extend" to promote a fixed record to a record scheme, and
   161     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   162     declared as simp by default;
   163   - removed "make_scheme" operations (use "make" with "extend") --
   164     INCOMPATIBILITY;
   165   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   166   - provides cases/induct rules for use with corresponding Isar
   167     methods (for concrete records, record schemes, concrete more
   168     parts, and schematic more parts -- in that order);
   169   - internal definitions directly based on a light-weight abstract
   170     theory of product types over typedef rather than datatype;
   171 
   172 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   173 
   174 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   175 (beware of argument permutation!);
   176 
   177 * HOL: linorder_less_split superseded by linorder_cases;
   178 
   179 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   180 to peripheral theory "Hilbert_Choice";
   181 
   182 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   183 in this (rare) case use:
   184 
   185   delSWrapper "split_all_tac"
   186   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   187 
   188 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   189 MAY FAIL;
   190 
   191 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   192 Isabelle's type classes, ^ on functions and relations has too general
   193 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   194 necessary to attach explicit type constraints;
   195 
   196 * HOL: syntax translations now work properly with numerals and records
   197 expressions;
   198 
   199 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   200 Florian Kammüller;
   201 
   202 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   203 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   204 renamed "Product_Type.unit";
   205 
   206 
   207 *** HOLCF ***
   208 
   209 * proper rep_datatype lift (see theory Lift) instead of ML hacks --
   210 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   211 lift.induct_tac, always use UU instead of Undef;
   212 
   213 
   214 *** ZF ***
   215 
   216 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   217 typeless version of the formalism;
   218 
   219 * ZF/Induct: new directory for examples of inductive definitions,
   220 including theory Multiset for multiset orderings;
   221 
   222 * ZF: the integer library now covers quotients and remainders, with
   223 many laws relating division to addition, multiplication, etc.;
   224 
   225 
   226 *** General ***
   227 
   228 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   229 variable proof controls level of detail: 0 = no proofs (only oracle
   230 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   231 also ref manual for further ML interfaces;
   232 
   233 * Pure/axclass: removed obsolete ML interface
   234 goal_subclass/goal_arity;
   235 
   236 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   237 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   238 separate tokens, so expressions involving minus need to be spaced
   239 properly;
   240 
   241 * Pure/syntax: support non-oriented infixes;
   242 
   243 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   244 control output of nested => (types); the default behavior is
   245 "type_brackets";
   246 
   247 * Pure/syntax: builtin parse translation for "_constify" turns valued
   248 tokens into AST constants;
   249 
   250 * Pure/syntax: prefer later declarations of translations and print
   251 translation functions; potential INCOMPATIBILITY: need to reverse
   252 multiple declarations for same syntax element constant;
   253 
   254 * Provers/classical: renamed addaltern to addafter, addSaltern to
   255 addSafter;
   256 
   257 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   258 as well;
   259 
   260 * system: refrain from any attempt at filtering input streams; no
   261 longer support ``8bit'' encoding of old isabelle font, instead proper
   262 iso-latin characters may now be used;
   263 
   264 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   265 
   266 * system: Proof General keywords specification is now part of the
   267 Isabelle distribution (see etc/isar-keywords.el);
   268 
   269 * system: smart selection of Isabelle process versus Isabelle
   270 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   271 run both "isabelle" and "Isabelle" even if file names are badly
   272 damaged (executable inspects the case of the first letter of its own
   273 name); added separate "isabelle-process" and "isabelle-interface";
   274 
   275 
   276 
   277 New in Isabelle99-2 (February 2001)
   278 -----------------------------------
   279 
   280 *** Overview of INCOMPATIBILITIES ***
   281 
   282 * HOL: please note that theories in the Library and elsewhere often use the
   283 new-style (Isar) format; to refer to their theorems in an ML script you must
   284 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   285 
   286 * HOL: inductive package no longer splits induction rule aggressively,
   287 but only as far as specified by the introductions given; the old
   288 format may be recovered via ML function complete_split_rule or attribute
   289 'split_rule (complete)';
   290 
   291 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   292 gfp_Tarski to gfp_unfold;
   293 
   294 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   295 
   296 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   297 relation); infix "^^" has been renamed "``"; infix "``" has been
   298 renamed "`"; "univalent" has been renamed "single_valued";
   299 
   300 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   301 operation;
   302 
   303 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   304 
   305 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   306 
   307 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   308 consequence, it is no longer monotonic wrt. the local goal context
   309 (which is now passed through the inductive cases);
   310 
   311 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   312 \<gg> to \<ggreater>;
   313 
   314 
   315 *** Document preparation ***
   316 
   317 * \isabellestyle{NAME} selects version of Isabelle output (currently
   318 available: are "it" for near math-mode best-style output, "sl" for
   319 slanted text style, and "tt" for plain type-writer; if no
   320 \isabellestyle command is given, output is according to slanted
   321 type-writer);
   322 
   323 * support sub/super scripts (for single symbols only), input syntax is
   324 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   325 
   326 * some more standard symbols; see Appendix A of the system manual for
   327 the complete list of symbols defined in isabellesym.sty;
   328 
   329 * improved isabelle style files; more abstract symbol implementation
   330 (should now use \isamath{...} and \isatext{...} in custom symbol
   331 definitions);
   332 
   333 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   334 state; Note that presentation of goal states does not conform to
   335 actual human-readable proof documents.  Please do not include goal
   336 states into document output unless you really know what you are doing!
   337 
   338 * proper indentation of antiquoted output with proportional LaTeX
   339 fonts;
   340 
   341 * no_document ML operator temporarily disables LaTeX document
   342 generation;
   343 
   344 * isatool unsymbolize tunes sources for plain ASCII communication;
   345 
   346 
   347 *** Isar ***
   348 
   349 * Pure: Isar now suffers initial goal statements to contain unbound
   350 schematic variables (this does not conform to actual readable proof
   351 documents, due to unpredictable outcome and non-compositional proof
   352 checking); users who know what they are doing may use schematic goals
   353 for Prolog-style synthesis of proven results;
   354 
   355 * Pure: assumption method (an implicit finishing) now handles actual
   356 rules as well;
   357 
   358 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   359 initial goal, declare "that" only as Pure intro (only for single
   360 steps); the "that" rule assumption may now be involved in implicit
   361 finishing, thus ".." becomes a feasible for trivial obtains;
   362 
   363 * Pure: default proof step now includes 'intro_classes'; thus trivial
   364 instance proofs may be performed by "..";
   365 
   366 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   367 statements as well;
   368 
   369 * Pure: more robust selection of calculational rules;
   370 
   371 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   372 rule (as well as the assumption rule);
   373 
   374 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   375 lemmas, using the graph browser tool;
   376 
   377 * Pure: predict failure of "show" in interactive mode;
   378 
   379 * Pure: 'thms_containing' now takes actual terms as arguments;
   380 
   381 * HOL: improved method 'induct' --- now handles non-atomic goals
   382 (potential INCOMPATIBILITY); tuned error handling;
   383 
   384 * HOL: cases and induct rules now provide explicit hints about the
   385 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   386 any remaining facts are inserted into the goal verbatim;
   387 
   388 * HOL: local contexts (aka cases) may now contain term bindings as
   389 well; the 'cases' and 'induct' methods new provide a ?case binding for
   390 the result to be shown in each case;
   391 
   392 * HOL: added 'recdef_tc' command;
   393 
   394 * isatool convert assists in eliminating legacy ML scripts;
   395 
   396 
   397 *** HOL ***
   398 
   399 * HOL/Library: a collection of generic theories to be used together
   400 with main HOL; the theory loader path already includes this directory
   401 by default; the following existing theories have been moved here:
   402 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   403 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   404 
   405 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   406 modelling and verification task performed in Isabelle/HOL +
   407 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   408 
   409 * HOL/Algebra: special summation operator SUM no longer exists, it has
   410 been replaced by setsum; infix 'assoc' now has priority 50 (like
   411 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   412 'domain', this makes the theory consistent with mathematical
   413 literature;
   414 
   415 * HOL basics: added overloaded operations "inverse" and "divide"
   416 (infix "/"), syntax for generic "abs" operation, generic summation
   417 operator \<Sum>;
   418 
   419 * HOL/typedef: simplified package, provide more useful rules (see also
   420 HOL/subset.thy);
   421 
   422 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   423 now expressed as a proper nested rule (old-style tactic scripts may
   424 require atomize_strip_tac to cope with non-atomic premises);
   425 
   426 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   427 to "split_conv" (old name still available for compatibility);
   428 
   429 * HOL: improved concrete syntax for strings (e.g. allows translation
   430 rules with string literals);
   431 
   432 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   433  and Fleuriot's mechanization of analysis, including the transcendental
   434  functions for the reals;
   435 
   436 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   437 
   438 
   439 *** CTT ***
   440 
   441 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   442 "lam" is displayed as TWO lambda-symbols
   443 
   444 * CTT: theory Main now available, containing everything (that is, Bool
   445 and Arith);
   446 
   447 
   448 *** General ***
   449 
   450 * Pure: the Simplifier has been implemented properly as a derived rule
   451 outside of the actual kernel (at last!); the overall performance
   452 penalty in practical applications is about 50%, while reliability of
   453 the Isabelle inference kernel has been greatly improved;
   454 
   455 * print modes "brackets" and "no_brackets" control output of nested =>
   456 (types) and ==> (props); the default behaviour is "brackets";
   457 
   458 * Provers: fast_tac (and friends) now handle actual object-logic rules
   459 as assumptions as well;
   460 
   461 * system: support Poly/ML 4.0;
   462 
   463 * system: isatool install handles KDE version 1 or 2;
   464 
   465 
   466 
   467 New in Isabelle99-1 (October 2000)
   468 ----------------------------------
   469 
   470 *** Overview of INCOMPATIBILITIES ***
   471 
   472 * HOL: simplification of natural numbers is much changed; to partly
   473 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   474 issue the following ML commands:
   475 
   476   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   477   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   478 
   479 * HOL: simplification no longer dives into case-expressions; this is
   480 controlled by "t.weak_case_cong" for each datatype t;
   481 
   482 * HOL: nat_less_induct renamed to less_induct;
   483 
   484 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   485 fixsome to patch .thy and .ML sources automatically;
   486 
   487   select_equality  -> some_equality
   488   select_eq_Ex     -> some_eq_ex
   489   selectI2EX       -> someI2_ex
   490   selectI2         -> someI2
   491   selectI          -> someI
   492   select1_equality -> some1_equality
   493   Eps_sym_eq       -> some_sym_eq_trivial
   494   Eps_eq           -> some_eq_trivial
   495 
   496 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   497 
   498 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   499 instead);
   500 
   501 * HOL: the recursion equations generated by 'recdef' are now called
   502 f.simps instead of f.rules;
   503 
   504 * HOL: qed_spec_mp now also handles bounded ALL as well;
   505 
   506 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   507 sometimes be needed;
   508 
   509 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   510 
   511 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   512 
   513 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   514 product is now "<*>" instead of "Times"; the lexicographic product is
   515 now "<*lex*>" instead of "**";
   516 
   517 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   518 of main HOL, but was unused); better use HOL's datatype package;
   519 
   520 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   521 the old syntax may be recovered as follows:
   522 
   523   syntax (symbols)
   524     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   525       (infixl "\\<oplus>" 100)
   526 
   527 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   528 
   529 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   530 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   531 internally;
   532 
   533 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   534 changed from A/r to A//r;
   535 
   536 * ZF: new treatment of arithmetic (nat & int) may break some old
   537 proofs;
   538 
   539 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   540 rulify -> rule_format, elimify -> elim_format, ...);
   541 
   542 * Isar/Provers: intro/elim/dest attributes changed; renamed
   543 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   544 should have to change intro!! to intro? only); replaced "delrule" by
   545 "rule del";
   546 
   547 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   548 
   549 * Provers: strengthened force_tac by using new first_best_tac;
   550 
   551 * LaTeX document preparation: several changes of isabelle.sty (see
   552 lib/texinputs);
   553 
   554 
   555 *** Document preparation ***
   556 
   557 * formal comments (text blocks etc.) in new-style theories may now
   558 contain antiquotations of thm/prop/term/typ/text to be presented
   559 according to latex print mode; concrete syntax is like this:
   560 @{term[show_types] "f(x) = a + x"};
   561 
   562 * isatool mkdir provides easy setup of Isabelle session directories,
   563 including proper document sources;
   564 
   565 * generated LaTeX sources are now deleted after successful run
   566 (isatool document -c); may retain a copy somewhere else via -D option
   567 of isatool usedir;
   568 
   569 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   570 style files, achieving self-contained LaTeX sources and simplifying
   571 LaTeX debugging;
   572 
   573 * old-style theories now produce (crude) LaTeX output as well;
   574 
   575 * browser info session directories are now self-contained (may be put
   576 on WWW server seperately); improved graphs of nested sessions; removed
   577 graph for 'all sessions';
   578 
   579 * several improvements in isabelle style files; \isabellestyle{it}
   580 produces fake math mode output; \isamarkupheader is now \section by
   581 default; see lib/texinputs/isabelle.sty etc.;
   582 
   583 
   584 *** Isar ***
   585 
   586 * Isar/Pure: local results and corresponding term bindings are now
   587 subject to Hindley-Milner polymorphism (similar to ML); this
   588 accommodates incremental type-inference very nicely;
   589 
   590 * Isar/Pure: new derived language element 'obtain' supports
   591 generalized existence reasoning;
   592 
   593 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   594 support accumulation of results, without applying any rules yet;
   595 useful to collect intermediate results without explicit name
   596 references, and for use with transitivity rules with more than 2
   597 premises;
   598 
   599 * Isar/Pure: scalable support for case-analysis type proofs: new
   600 'case' language element refers to local contexts symbolically, as
   601 produced by certain proof methods; internally, case names are attached
   602 to theorems as "tags";
   603 
   604 * Isar/Pure: theory command 'hide' removes declarations from
   605 class/type/const name spaces;
   606 
   607 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   608 indicate potential overloading;
   609 
   610 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   611 
   612 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   613 "{a,b,c}" instead of {a,b,c};
   614 
   615 * Isar/Pure now provides its own version of intro/elim/dest
   616 attributes; useful for building new logics, but beware of confusion
   617 with the version in Provers/classical;
   618 
   619 * Isar/Pure: the local context of (non-atomic) goals is provided via
   620 case name 'antecedent';
   621 
   622 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   623 to the current context is now done automatically);
   624 
   625 * Isar/Pure: theory command 'method_setup' provides a simple interface
   626 for definining proof methods in ML;
   627 
   628 * Isar/Provers: intro/elim/dest attributes changed; renamed
   629 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   630 most cases, one should have to change intro!! to intro? only);
   631 replaced "delrule" by "rule del";
   632 
   633 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   634 'symmetric' attribute (the latter supercedes [RS sym]);
   635 
   636 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   637 method modifier); 'simp' method: 'only:' modifier removes loopers as
   638 well (including splits);
   639 
   640 * Isar/Provers: Simplifier and Classical methods now support all kind
   641 of modifiers used in the past, including 'cong', 'iff', etc.
   642 
   643 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   644 of Simplifier and Classical reasoner);
   645 
   646 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   647 now support named cases; major packages (inductive, datatype, primrec,
   648 recdef) support case names and properly name parameters;
   649 
   650 * Isar/HOL: new transitivity rules for substitution in inequalities --
   651 monotonicity conditions are extracted to be proven at end of
   652 calculations;
   653 
   654 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   655 method anyway;
   656 
   657 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   658 split_if split_if_asm; datatype package provides theorems foo.splits =
   659 foo.split foo.split_asm for each datatype;
   660 
   661 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   662 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   663 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   664 use "(cases (simplified))" method in proper proof texts);
   665 
   666 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   667 
   668 * Isar: names of theorems etc. may be natural numbers as well;
   669 
   670 * Isar: 'pr' command: optional arguments for goals_limit and
   671 ProofContext.prems_limit; no longer prints theory contexts, but only
   672 proof states;
   673 
   674 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   675 additional print modes to be specified; e.g. "pr(latex)" will print
   676 proof state according to the Isabelle LaTeX style;
   677 
   678 * Isar: improved support for emulating tactic scripts, including proof
   679 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   680 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   681 (for HOL datatypes);
   682 
   683 * Isar: simplified (more robust) goal selection of proof methods: 1st
   684 goal, all goals, or explicit goal specifier (tactic emulation); thus
   685 'proof method scripts' have to be in depth-first order;
   686 
   687 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   688 
   689 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   690 should instead use individual commands for printing items
   691 (print_commands, print_methods etc.);
   692 
   693 * Isar: added 'nothing' --- the empty list of theorems;
   694 
   695 
   696 *** HOL ***
   697 
   698 * HOL/MicroJava: formalization of a fragment of Java, together with a
   699 corresponding virtual machine and a specification of its bytecode
   700 verifier and a lightweight bytecode verifier, including proofs of
   701 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   702 Cornelia Pusch (see also the homepage of project Bali at
   703 http://isabelle.in.tum.de/Bali/);
   704 
   705 * HOL/Algebra: new theory of rings and univariate polynomials, by
   706 Clemens Ballarin;
   707 
   708 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   709 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   710 Rasmussen;
   711 
   712 * HOL/Lattice: fundamental concepts of lattice theory and order
   713 structures, including duals, properties of bounds versus algebraic
   714 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   715 Theorem for complete lattices etc.; may also serve as a demonstration
   716 for abstract algebraic reasoning using axiomatic type classes, and
   717 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   718 
   719 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   720 von Oheimb;
   721 
   722 * HOL/IMPP: extension of IMP with local variables and mutually
   723 recursive procedures, by David von Oheimb;
   724 
   725 * HOL/Lambda: converted into new-style theory and document;
   726 
   727 * HOL/ex/Multiquote: example of multiple nested quotations and
   728 anti-quotations -- basically a generalized version of de-Bruijn
   729 representation; very useful in avoiding lifting of operations;
   730 
   731 * HOL/record: added general record equality rule to simpset; fixed
   732 select-update simplification procedure to handle extended records as
   733 well; admit "r" as field name;
   734 
   735 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   736 other numeric types and also as the identity of groups, rings, etc.;
   737 
   738 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   739 Types nat and int belong to this axclass;
   740 
   741 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   742    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   743    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   744   two terms #m*u and #n*u are replaced by #(m+n)*u
   745     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   746   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   747     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   748 
   749 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   750 powerful prover for predicate logic but knows nothing of clasets; see
   751 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   752 
   753 * HOL: new version of "case_tac" subsumes both boolean case split and
   754 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   755 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   756 
   757 * HOL: simplification no longer dives into case-expressions: only the
   758 selector expression is simplified, but not the remaining arms; to
   759 enable full simplification of case-expressions for datatype t, you may
   760 remove t.weak_case_cong from the simpset, either globally (Delcongs
   761 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   762 
   763 * HOL/recdef: the recursion equations generated by 'recdef' for
   764 function 'f' are now called f.simps instead of f.rules; if all
   765 termination conditions are proved automatically, these simplification
   766 rules are added to the simpset, as in primrec; rules may be named
   767 individually as well, resulting in a separate list of theorems for
   768 each equation;
   769 
   770 * HOL/While is a new theory that provides a while-combinator. It
   771 permits the definition of tail-recursive functions without the
   772 provision of a termination measure. The latter is necessary once the
   773 invariant proof rule for while is applied.
   774 
   775 * HOL: new (overloaded) notation for the set of elements below/above
   776 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   777 
   778 * HOL: theorems impI, allI, ballI bound as "strip";
   779 
   780 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   781 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   782 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   783 
   784 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   785 
   786 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   787 main HOL, but was unused);
   788 
   789 * HOL: fewer consts declared as global (e.g. have to refer to
   790 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   791 
   792 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   793 in case of overlap with user translations (e.g. judgements over
   794 tuples); (note that the underlying logical represenation is still
   795 bogus);
   796 
   797 
   798 *** ZF ***
   799 
   800 * ZF: simplification automatically cancels common terms in arithmetic
   801 expressions over nat and int;
   802 
   803 * ZF: new treatment of nat to minimize type-checking: all operators
   804 coerce their operands to a natural number using the function natify,
   805 making the algebraic laws unconditional;
   806 
   807 * ZF: as above, for int: operators coerce their operands to an integer
   808 using the function intify;
   809 
   810 * ZF: the integer library now contains many of the usual laws for the
   811 orderings, including $<=, and monotonicity laws for $+ and $*;
   812 
   813 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   814 simplification;
   815 
   816 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   817 to the simplifier and classical reasoner simultaneously;
   818 
   819 
   820 *** General ***
   821 
   822 * Provers: blast_tac now handles actual object-logic rules as
   823 assumptions; note that auto_tac uses blast_tac internally as well;
   824 
   825 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   826 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   827 
   828 * Provers: delrules now handles destruct rules as well (no longer need
   829 explicit make_elim);
   830 
   831 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   832   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   833 use instead the strong form,
   834   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   835 in HOL, FOL and ZF the function cla_make_elim will create such rules
   836 from destruct-rules;
   837 
   838 * Provers: Simplifier.easy_setup provides a fast path to basic
   839 Simplifier setup for new object-logics;
   840 
   841 * Pure: AST translation rules no longer require constant head on LHS;
   842 
   843 * Pure: improved name spaces: ambiguous output is qualified; support
   844 for hiding of names;
   845 
   846 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   847 XSYMBOL_HOME; no longer need to do manual configuration in most
   848 situations;
   849 
   850 * system: compression of ML heaps images may now be controlled via -c
   851 option of isabelle and isatool usedir (currently only observed by
   852 Poly/ML);
   853 
   854 * system: isatool installfonts may handle X-Symbol fonts as well (very
   855 useful for remote X11);
   856 
   857 * system: provide TAGS file for Isabelle sources;
   858 
   859 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   860 order;
   861 
   862 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   863 timing flag supersedes proof_timing and Toplevel.trace;
   864 
   865 * ML: new combinators |>> and |>>> for incremental transformations
   866 with secondary results (e.g. certain theory extensions):
   867 
   868 * ML: PureThy.add_defs gets additional argument to indicate potential
   869 overloading (usually false);
   870 
   871 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   872 results;
   873 
   874 
   875 
   876 New in Isabelle99 (October 1999)
   877 --------------------------------
   878 
   879 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   880 
   881 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   882 are no longer simplified.  (This allows the simplifier to unfold recursive
   883 functional programs.)  To restore the old behaviour, declare
   884 
   885     Delcongs [if_weak_cong];
   886 
   887 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   888 complement;
   889 
   890 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   891 
   892 * HOL/datatype: mutual_induct_tac no longer exists --
   893   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   894 
   895 * HOL/typedef: fixed type inference for representing set; type
   896 arguments now have to occur explicitly on the rhs as type constraints;
   897 
   898 * ZF: The con_defs part of an inductive definition may no longer refer
   899 to constants declared in the same theory;
   900 
   901 * HOL, ZF: the function mk_cases, generated by the inductive
   902 definition package, has lost an argument.  To simplify its result, it
   903 uses the default simpset instead of a supplied list of theorems.
   904 
   905 * HOL/List: the constructors of type list are now Nil and Cons;
   906 
   907 * Simplifier: the type of the infix ML functions
   908         setSSolver addSSolver setSolver addSolver
   909 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   910 for packaging solvers. A solver is created via
   911         mk_solver: string -> (thm list -> int -> tactic) -> solver
   912 where the string argument is only a comment.
   913 
   914 
   915 *** Proof tools ***
   916 
   917 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   918 decision procedure for linear arithmetic. Currently it is used for
   919 types `nat', `int', and `real' in HOL (see below); it can, should and
   920 will be instantiated for other types and logics as well.
   921 
   922 * The simplifier now accepts rewrite rules with flexible heads, eg
   923      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   924   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   925   matching.
   926 
   927 
   928 *** General ***
   929 
   930 * New Isabelle/Isar subsystem provides an alternative to traditional
   931 tactical theorem proving; together with the ProofGeneral/isar user
   932 interface it offers an interactive environment for developing human
   933 readable proof documents (Isar == Intelligible semi-automated
   934 reasoning); for further information see isatool doc isar-ref,
   935 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   936 
   937 * improved and simplified presentation of theories: better HTML markup
   938 (including colors), graph views in several sizes; isatool usedir now
   939 provides a proper interface for user theories (via -P option); actual
   940 document preparation based on (PDF)LaTeX is available as well (for
   941 new-style theories only); see isatool doc system for more information;
   942 
   943 * native support for Proof General, both for classic Isabelle and
   944 Isabelle/Isar;
   945 
   946 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   947 using the graph browser tool;
   948 
   949 * Isabelle manuals now also available as PDF;
   950 
   951 * theory loader rewritten from scratch (may not be fully
   952 bug-compatible); old loadpath variable has been replaced by show_path,
   953 add_path, del_path, reset_path functions; new operations such as
   954 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   955 isatool doc ref);
   956 
   957 * improved isatool install: option -k creates KDE application icon,
   958 option -p DIR installs standalone binaries;
   959 
   960 * added ML_PLATFORM setting (useful for cross-platform installations);
   961 more robust handling of platform specific ML images for SML/NJ;
   962 
   963 * the settings environment is now statically scoped, i.e. it is never
   964 created again in sub-processes invoked from isabelle, isatool, or
   965 Isabelle;
   966 
   967 * path element specification '~~' refers to '$ISABELLE_HOME';
   968 
   969 * in locales, the "assumes" and "defines" parts may be omitted if
   970 empty;
   971 
   972 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   973 long arrows);
   974 
   975 * new print_mode "HTML";
   976 
   977 * new flag show_tags controls display of tags of theorems (which are
   978 basically just comments that may be attached by some tools);
   979 
   980 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   981 mode and goal output format:
   982 
   983 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   984 244c244
   985 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   986 ---
   987 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   988 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   989 181c181
   990 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   991 ---
   992 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   993 
   994 * function bind_thms stores lists of theorems (cf. bind_thm);
   995 
   996 * new shorthand tactics ftac, eatac, datac, fatac;
   997 
   998 * qed (and friends) now accept "" as result name; in that case the
   999 theorem is not stored, but proper checks and presentation of the
  1000 result still apply;
  1001 
  1002 * theorem database now also indexes constants "Trueprop", "all",
  1003 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1004 
  1005 
  1006 *** HOL ***
  1007 
  1008 ** HOL arithmetic **
  1009 
  1010 * There are now decision procedures for linear arithmetic over nat and
  1011 int:
  1012 
  1013 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1014 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1015 are treated as atomic; subformulae not involving type `nat' or `int'
  1016 are ignored; quantified subformulae are ignored unless they are
  1017 positive universal or negative existential. The tactic has to be
  1018 invoked by hand and can be a little bit slow. In particular, the
  1019 running time is exponential in the number of occurrences of `min' and
  1020 `max', and `-' on `nat'.
  1021 
  1022 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1023 (negated) (in)equalities among the premises and the conclusion into
  1024 account (i.e. no compound formulae) and does not know about `min' and
  1025 `max', and `-' on `nat'. It is fast and is used automatically by the
  1026 simplifier.
  1027 
  1028 NB: At the moment, these decision procedures do not cope with mixed
  1029 nat/int formulae where the two parts interact, such as `m < n ==>
  1030 int(m) < int(n)'.
  1031 
  1032 * HOL/Numeral provides a generic theory of numerals (encoded
  1033 efficiently as bit strings); setup for types nat/int/real is in place;
  1034 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1035 int, existing theories and proof scripts may require a few additional
  1036 type constraints;
  1037 
  1038 * integer division and remainder can now be performed on constant
  1039 arguments;
  1040 
  1041 * many properties of integer multiplication, division and remainder
  1042 are now available;
  1043 
  1044 * An interface to the Stanford Validity Checker (SVC) is available through the
  1045 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1046 are proved automatically.  SVC must be installed separately, and its results
  1047 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1048 invocation of the underlying oracle).  For SVC see
  1049   http://verify.stanford.edu/SVC
  1050 
  1051 * IsaMakefile: the HOL-Real target now builds an actual image;
  1052 
  1053 
  1054 ** HOL misc **
  1055 
  1056 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1057 (in Isabelle/Isar) -- by Gertrud Bauer;
  1058 
  1059 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1060 analysis for assembly languages with subtypes;
  1061 
  1062 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1063 -- avoids syntactic ambiguities and treats state, transition, and
  1064 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1065 changed syntax and (many) tactics;
  1066 
  1067 * HOL/inductive: Now also handles more general introduction rules such
  1068   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1069   theorems are now maintained within the theory (maintained via the
  1070   "mono" attribute);
  1071 
  1072 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1073   (using function types) such as
  1074 
  1075   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1076 
  1077 * HOL/record: record_simproc (part of the default simpset) takes care
  1078 of selectors applied to updated records; record_split_tac is no longer
  1079 part of the default claset; update_defs may now be removed from the
  1080 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1081 
  1082   claset_ref () := claset() addSWrapper record_split_wrapper;
  1083   Delsimprocs [record_simproc]
  1084 
  1085 * HOL/typedef: fixed type inference for representing set; type
  1086 arguments now have to occur explicitly on the rhs as type constraints;
  1087 
  1088 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1089 names rather than an ML expression;
  1090 
  1091 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1092 supplied later.  Program schemes can be defined, such as
  1093     "While B C s = (if B s then While B C (C s) else s)"
  1094 where the well-founded relation can be chosen after B and C have been given.
  1095 
  1096 * HOL/List: the constructors of type list are now Nil and Cons;
  1097 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1098 course, ML tools referring to List.list.op # etc. have to be adapted;
  1099 
  1100 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1101 disabled by default; run isabelle with option -m HOL to get back to
  1102 the original Gordon/HOL-style output;
  1103 
  1104 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1105 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1106 
  1107 * HOL basic syntax simplified (more orthogonal): all variants of
  1108 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1109 Eps operator is provided as well: "SOME x. P[x]";
  1110 
  1111 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1112 
  1113 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1114 thus available for user theories;
  1115 
  1116 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1117 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1118 time;
  1119 
  1120 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1121 several times and then mp;
  1122 
  1123 
  1124 *** LK ***
  1125 
  1126 * the notation <<...>> is now available as a notation for sequences of
  1127 formulas;
  1128 
  1129 * the simplifier is now installed
  1130 
  1131 * the axiom system has been generalized (thanks to Soren Heilmann)
  1132 
  1133 * the classical reasoner now has a default rule database
  1134 
  1135 
  1136 *** ZF ***
  1137 
  1138 * new primrec section allows primitive recursive functions to be given
  1139 directly (as in HOL) over datatypes and the natural numbers;
  1140 
  1141 * new tactics induct_tac and exhaust_tac for induction (or case
  1142 analysis) over datatypes and the natural numbers;
  1143 
  1144 * the datatype declaration of type T now defines the recursor T_rec;
  1145 
  1146 * simplification automatically does freeness reasoning for datatype
  1147 constructors;
  1148 
  1149 * automatic type-inference, with AddTCs command to insert new
  1150 type-checking rules;
  1151 
  1152 * datatype introduction rules are now added as Safe Introduction rules
  1153 to the claset;
  1154 
  1155 * the syntax "if P then x else y" is now available in addition to
  1156 if(P,x,y);
  1157 
  1158 
  1159 *** Internal programming interfaces ***
  1160 
  1161 * tuned simplifier trace output; new flag debug_simp;
  1162 
  1163 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1164 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1165 
  1166 * AxClass.axclass_tac lost the theory argument;
  1167 
  1168 * tuned current_goals_markers semantics: begin / end goal avoids
  1169 printing empty lines;
  1170 
  1171 * removed prs and prs_fn hook, which was broken because it did not
  1172 include \n in its semantics, forcing writeln to add one
  1173 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1174 string -> unit if you really want to output text without newline;
  1175 
  1176 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1177 plain output, interface builders may have to enable 'isabelle_font'
  1178 mode to get Isabelle font glyphs as before;
  1179 
  1180 * refined token_translation interface; INCOMPATIBILITY: output length
  1181 now of type real instead of int;
  1182 
  1183 * theory loader actions may be traced via new ThyInfo.add_hook
  1184 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1185 your own database of information attached to *whole* theories -- as
  1186 opposed to intra-theory data slots offered via TheoryDataFun;
  1187 
  1188 * proper handling of dangling sort hypotheses (at last!);
  1189 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1190 extra sort hypotheses that can be witnessed from the type signature;
  1191 the force_strip_shyps flag is gone, any remaining shyps are simply
  1192 left in the theorem (with a warning issued by strip_shyps_warning);
  1193 
  1194 
  1195 
  1196 New in Isabelle98-1 (October 1998)
  1197 ----------------------------------
  1198 
  1199 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1200 
  1201 * several changes of automated proof tools;
  1202 
  1203 * HOL: major changes to the inductive and datatype packages, including
  1204 some minor incompatibilities of theory syntax;
  1205 
  1206 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1207 called `inj_on';
  1208 
  1209 * HOL: removed duplicate thms in Arith:
  1210   less_imp_add_less  should be replaced by  trans_less_add1
  1211   le_imp_add_le      should be replaced by  trans_le_add1
  1212 
  1213 * HOL: unary minus is now overloaded (new type constraints may be
  1214 required);
  1215 
  1216 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1217 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1218 now taken as an integer constant.
  1219 
  1220 * Pure: ML function 'theory_of' renamed to 'theory';
  1221 
  1222 
  1223 *** Proof tools ***
  1224 
  1225 * Simplifier:
  1226   1. Asm_full_simp_tac is now more aggressive.
  1227      1. It will sometimes reorient premises if that increases their power to
  1228         simplify.
  1229      2. It does no longer proceed strictly from left to right but may also
  1230         rotate premises to achieve further simplification.
  1231      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1232      old Asm_full_simp_tac in that it does not rotate premises.
  1233   2. The simplifier now knows a little bit about nat-arithmetic.
  1234 
  1235 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1236 allows for selected deletion of wrappers, by introduction of names for
  1237 wrapper functionals.  This implies that addbefore, addSbefore,
  1238 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1239 and that adding two tactics with the same name overwrites the first
  1240 one (emitting a warning).
  1241   type wrapper = (int -> tactic) -> (int -> tactic)
  1242   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1243   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1244   delWrapper, delSWrapper: claset *  string            -> claset
  1245   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1246 
  1247 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1248 semantics; addbefore now affects only the unsafe part of step_tac
  1249 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1250 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1251 by Force_tac;
  1252 
  1253 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1254 compWrapper; added safe wrapper (and access functions for it);
  1255 
  1256 * HOL/split_all_tac is now much faster and fails if there is nothing
  1257 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1258 and the names of the automatically generated variables have changed.
  1259 split_all_tac has moved within claset() from unsafe wrappers to safe
  1260 wrappers, which means that !!-bound variables are split much more
  1261 aggressively, and safe_tac and clarify_tac now split such variables.
  1262 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1263 Note: the same holds for record_split_tac, which does the job of
  1264 split_all_tac for record fields.
  1265 
  1266 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1267 permanently to the default simpset using Addsplits just like
  1268 Addsimps. They can be removed via Delsplits just like
  1269 Delsimps. Lower-case versions are also available.
  1270 
  1271 * HOL/Simplifier: The rule split_if is now part of the default
  1272 simpset. This means that the simplifier will eliminate all occurrences
  1273 of if-then-else in the conclusion of a goal. To prevent this, you can
  1274 either remove split_if completely from the default simpset by
  1275 `Delsplits [split_if]' or remove it in a specific call of the
  1276 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1277 other case splitting rules to/from the default simpset: every datatype
  1278 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1279 t is the name of the datatype).
  1280 
  1281 * Classical reasoner / Simplifier combination: new force_tac (and
  1282 derivatives Force_tac, force) combines rewriting and classical
  1283 reasoning (and whatever other tools) similarly to auto_tac, but is
  1284 aimed to solve the given subgoal completely.
  1285 
  1286 
  1287 *** General ***
  1288 
  1289 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1290 and `goalw': the theory is no longer needed as an explicit argument -
  1291 the current theory context is used; assumptions are no longer returned
  1292 at the ML-level unless one of them starts with ==> or !!; it is
  1293 recommended to convert to these new commands using isatool fixgoal
  1294 (backup your sources first!);
  1295 
  1296 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1297 the current theory context, and 'theory' to lookup stored theories;
  1298 
  1299 * new theory section 'locale' for declaring constants, assumptions and
  1300 definitions that have local scope;
  1301 
  1302 * new theory section 'nonterminals' for purely syntactic types;
  1303 
  1304 * new theory section 'setup' for generic ML setup functions
  1305 (e.g. package initialization);
  1306 
  1307 * the distribution now includes Isabelle icons: see
  1308 lib/logo/isabelle-{small,tiny}.xpm;
  1309 
  1310 * isatool install - install binaries with absolute references to
  1311 ISABELLE_HOME/bin;
  1312 
  1313 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1314 
  1315 * print mode 'emacs' reserved for Isamode;
  1316 
  1317 * support multiple print (ast) translations per constant name;
  1318 
  1319 * theorems involving oracles are now printed with a suffixed [!];
  1320 
  1321 
  1322 *** HOL ***
  1323 
  1324 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1325 
  1326 * HOL/inductive package reorganized and improved: now supports mutual
  1327 definitions such as
  1328 
  1329   inductive EVEN ODD
  1330     intrs
  1331       null "0 : EVEN"
  1332       oddI "n : EVEN ==> Suc n : ODD"
  1333       evenI "n : ODD ==> Suc n : EVEN"
  1334 
  1335 new theorem list "elims" contains an elimination rule for each of the
  1336 recursive sets; inductive definitions now handle disjunctive premises
  1337 correctly (also ZF);
  1338 
  1339 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1340 "mutual_induct" no longer exists - the induction rule is always
  1341 contained in "induct";
  1342 
  1343 
  1344 * HOL/datatype package re-implemented and greatly improved: now
  1345 supports mutually recursive datatypes such as
  1346 
  1347   datatype
  1348     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1349             | SUM ('a aexp) ('a aexp)
  1350             | DIFF ('a aexp) ('a aexp)
  1351             | NUM 'a
  1352   and
  1353     'a bexp = LESS ('a aexp) ('a aexp)
  1354             | AND ('a bexp) ('a bexp)
  1355             | OR ('a bexp) ('a bexp)
  1356 
  1357 as well as indirectly recursive datatypes such as
  1358 
  1359   datatype
  1360     ('a, 'b) term = Var 'a
  1361                   | App 'b ((('a, 'b) term) list)
  1362 
  1363 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1364 induction on mutually / indirectly recursive datatypes.
  1365 
  1366 Primrec equations are now stored in theory and can be accessed via
  1367 <function_name>.simps.
  1368 
  1369 INCOMPATIBILITIES:
  1370 
  1371   - Theories using datatypes must now have theory Datatype as an
  1372     ancestor.
  1373   - The specific <typename>.induct_tac no longer exists - use the
  1374     generic induct_tac instead.
  1375   - natE has been renamed to nat.exhaust - use exhaust_tac
  1376     instead of res_inst_tac ... natE. Note that the variable
  1377     names in nat.exhaust differ from the names in natE, this
  1378     may cause some "fragile" proofs to fail.
  1379   - The theorems split_<typename>_case and split_<typename>_case_asm
  1380     have been renamed to <typename>.split and <typename>.split_asm.
  1381   - Since default sorts of type variables are now handled correctly,
  1382     some datatype definitions may have to be annotated with explicit
  1383     sort constraints.
  1384   - Primrec definitions no longer require function name and type
  1385     of recursive argument.
  1386 
  1387 Consider using isatool fixdatatype to adapt your theories and proof
  1388 scripts to the new package (backup your sources first!).
  1389 
  1390 
  1391 * HOL/record package: considerably improved implementation; now
  1392 includes concrete syntax for record types, terms, updates; theorems
  1393 for surjective pairing and splitting !!-bound record variables; proof
  1394 support is as follows:
  1395 
  1396   1) standard conversions (selectors or updates applied to record
  1397 constructor terms) are part of the standard simpset;
  1398 
  1399   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1400 made part of standard simpset and claset via addIffs;
  1401 
  1402   3) a tactic for record field splitting (record_split_tac) is part of
  1403 the standard claset (addSWrapper);
  1404 
  1405 To get a better idea about these rules you may retrieve them via
  1406 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1407 the name of your record type.
  1408 
  1409 The split tactic 3) conceptually simplifies by the following rule:
  1410 
  1411   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1412 
  1413 Thus any record variable that is bound by meta-all will automatically
  1414 blow up into some record constructor term, consequently the
  1415 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1416 solve record problems automatically.
  1417 
  1418 
  1419 * reorganized the main HOL image: HOL/Integ and String loaded by
  1420 default; theory Main includes everything;
  1421 
  1422 * automatic simplification of integer sums and comparisons, using cancellation;
  1423 
  1424 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1425 
  1426 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1427 
  1428 * many new identities for unions, intersections, set difference, etc.;
  1429 
  1430 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1431 called split_if, split_split, split_sum_case and split_nat_case (to go
  1432 with add/delsplits);
  1433 
  1434 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1435 (?x::unit) = (); this is made part of the default simpset, which COULD
  1436 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1437 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1438 unit_abs_eta_conv is added in order to counter the effect of
  1439 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1440 %u.f();
  1441 
  1442 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1443 makes more sense);
  1444 
  1445 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1446   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1447   disjointness reasoning but breaking a few old proofs.
  1448 
  1449 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1450 to 'converse' from 'inverse' (for compatibility with ZF and some
  1451 literature);
  1452 
  1453 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1454 the well-founded relation;
  1455 
  1456 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1457     Compl A.  The "Compl" syntax remains available as input syntax for this
  1458     release ONLY.
  1459 
  1460 * HOL/Update: new theory of function updates:
  1461     f(a:=b) == %x. if x=a then b else f x
  1462 may also be iterated as in f(a:=b,c:=d,...);
  1463 
  1464 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1465 
  1466 * HOL/List:
  1467   - new function list_update written xs[i:=v] that updates the i-th
  1468     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1469   - new function `upt' written [i..j(] which generates the list
  1470     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1471     bound write [i..j], which is a shorthand for [i..j+1(].
  1472   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1473 
  1474 * HOL/Arith:
  1475   - removed 'pred' (predecessor) function;
  1476   - generalized some theorems about n-1;
  1477   - many new laws about "div" and "mod";
  1478   - new laws about greatest common divisors (see theory ex/Primes);
  1479 
  1480 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1481 instead of "inverse";
  1482 
  1483 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1484   of the multiset ordering;
  1485 
  1486 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1487   (not included by default);
  1488 
  1489 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1490 
  1491 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1492   programs, i.e. different program variables may have different types.
  1493 
  1494 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1495   [previously, this check worked only if the rewrite rule was unconditional]
  1496   Now rew can involve either definitions or equalities (either == or =).
  1497 
  1498 
  1499 *** ZF ***
  1500 
  1501 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1502   only the theorems proved on ZF.ML;
  1503 
  1504 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1505   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1506   disjointness reasoning but breaking a few old proofs.
  1507 
  1508 * ZF/Update: new theory of function updates
  1509     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1510   may also be iterated as in f(a:=b,c:=d,...);
  1511 
  1512 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1513 
  1514 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1515   [previously, this check worked only if the rewrite rule was unconditional]
  1516   Now rew can involve either definitions or equalities (either == or =).
  1517 
  1518 * case_tac provided for compatibility with HOL
  1519     (like the old excluded_middle_tac, but with subgoals swapped)
  1520 
  1521 
  1522 *** Internal programming interfaces ***
  1523 
  1524 * Pure: several new basic modules made available for general use, see
  1525 also src/Pure/README;
  1526 
  1527 * improved the theory data mechanism to support encapsulation (data
  1528 kind name replaced by private Object.kind, acting as authorization
  1529 key); new type-safe user interface via functor TheoryDataFun; generic
  1530 print_data function becomes basically useless;
  1531 
  1532 * removed global_names compatibility flag -- all theory declarations
  1533 are qualified by default;
  1534 
  1535 * module Pure/Syntax now offers quote / antiquote translation
  1536 functions (useful for Hoare logic etc. with implicit dependencies);
  1537 see HOL/ex/Antiquote for an example use;
  1538 
  1539 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1540 cterm -> thm;
  1541 
  1542 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1543 subgoal;
  1544 
  1545 * Display.print_goals function moved to Locale.print_goals;
  1546 
  1547 * standard print function for goals supports current_goals_markers
  1548 variable for marking begin of proof, end of proof, start of goal; the
  1549 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1550 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1551 for example;
  1552 
  1553 
  1554 
  1555 New in Isabelle98 (January 1998)
  1556 --------------------------------
  1557 
  1558 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1559 
  1560 * changed lexical syntax of terms / types: dots made part of long
  1561 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1562 
  1563 * simpset (and claset) reference variable replaced by functions
  1564 simpset / simpset_ref;
  1565 
  1566 * no longer supports theory aliases (via merge) and non-trivial
  1567 implicit merge of thms' signatures;
  1568 
  1569 * most internal names of constants changed due to qualified names;
  1570 
  1571 * changed Pure/Sequence interface (see Pure/seq.ML);
  1572 
  1573 
  1574 *** General Changes ***
  1575 
  1576 * hierachically structured name spaces (for consts, types, axms, thms
  1577 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1578 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1579 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1580 long_names for fully qualified output names; NOTE: ML programs
  1581 (special tactics, packages etc.) referring to internal names may have
  1582 to be adapted to cope with fully qualified names; in case of severe
  1583 backward campatibility problems try setting 'global_names' at compile
  1584 time to have enrything declared within a flat name space; one may also
  1585 fine tune name declarations in theories via the 'global' and 'local'
  1586 section;
  1587 
  1588 * reimplemented the implicit simpset and claset using the new anytype
  1589 data filed in signatures; references simpset:simpset ref etc. are
  1590 replaced by functions simpset:unit->simpset and
  1591 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1592 to patch your ML files accordingly;
  1593 
  1594 * HTML output now includes theory graph data for display with Java
  1595 applet or isatool browser; data generated automatically via isatool
  1596 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1597 
  1598 * defs may now be conditional; improved rewrite_goals_tac to handle
  1599 conditional equations;
  1600 
  1601 * defs now admits additional type arguments, using TYPE('a) syntax;
  1602 
  1603 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1604 creates a new theory node; implicit merge of thms' signatures is
  1605 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1606 transfer:theory->thm->thm in (rare) cases;
  1607 
  1608 * improved handling of draft signatures / theories; draft thms (and
  1609 ctyps, cterms) are automatically promoted to real ones;
  1610 
  1611 * slightly changed interfaces for oracles: admit many per theory, named
  1612 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1613 
  1614 * print_goals: optional output of const types (set show_consts and
  1615 show_types);
  1616 
  1617 * improved output of warnings (###) and errors (***);
  1618 
  1619 * subgoal_tac displays a warning if the new subgoal has type variables;
  1620 
  1621 * removed old README and Makefiles;
  1622 
  1623 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1624 
  1625 * removed obsolete init_pps and init_database;
  1626 
  1627 * deleted the obsolete tactical STATE, which was declared by
  1628     fun STATE tacfun st = tacfun st st;
  1629 
  1630 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1631 (which abbreviates $HOME);
  1632 
  1633 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1634 use isatool fixseq to adapt your ML programs (this works for fully
  1635 qualified references to the Sequence structure only!);
  1636 
  1637 * use_thy no longer requires writable current directory; it always
  1638 reloads .ML *and* .thy file, if either one is out of date;
  1639 
  1640 
  1641 *** Classical Reasoner ***
  1642 
  1643 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1644 tactics that use classical reasoning to simplify a subgoal without
  1645 splitting it into several subgoals;
  1646 
  1647 * Safe_tac: like safe_tac but uses the default claset;
  1648 
  1649 
  1650 *** Simplifier ***
  1651 
  1652 * added simplification meta rules:
  1653     (asm_)(full_)simplify: simpset -> thm -> thm;
  1654 
  1655 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1656 logics (again);
  1657 
  1658 * added prems argument to simplification procedures;
  1659 
  1660 * HOL, FOL, ZF: added infix function `addsplits':
  1661   instead of `<simpset> setloop (split_tac <thms>)'
  1662   you can simply write `<simpset> addsplits <thms>'
  1663 
  1664 
  1665 *** Syntax ***
  1666 
  1667 * TYPE('a) syntax for type reflection terms;
  1668 
  1669 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1670 
  1671 * pretty printer: changed order of mixfix annotation preference (again!);
  1672 
  1673 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1674 
  1675 
  1676 *** HOL ***
  1677 
  1678 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1679   with `addloop' of the simplifier to faciliate case splitting in premises.
  1680 
  1681 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1682 
  1683 * HOL/Auth: new protocol proofs including some for the Internet
  1684   protocol TLS;
  1685 
  1686 * HOL/Map: new theory of `maps' a la VDM;
  1687 
  1688 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1689 cancelling out common nat summands from =, <, <= (in)equalities, or
  1690 differences; simplification procedures nat_cancel_factor for
  1691 cancelling common factor from =, <, <= (in)equalities over natural
  1692 sums; nat_cancel contains both kinds of procedures, it is installed by
  1693 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1694 
  1695 * HOL/simplifier: terms of the form
  1696   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1697   are rewritten to
  1698   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1699   and those of the form
  1700   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1701   are rewritten to
  1702   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1703 
  1704 * HOL/datatype
  1705   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1706 
  1707   P(t_case f1 ... fn x) =
  1708      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1709         ...
  1710        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1711      )
  1712 
  1713   and a theorem `split_t_case_asm' of the form
  1714 
  1715   P(t_case f1 ... fn x) =
  1716     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1717         ...
  1718        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1719      )
  1720   which can be added to a simpset via `addsplits'. The existing theorems
  1721   expand_list_case and expand_option_case have been renamed to
  1722   split_list_case and split_option_case.
  1723 
  1724 * HOL/Arithmetic:
  1725   - `pred n' is automatically converted to `n-1'.
  1726     Users are strongly encouraged not to use `pred' any longer,
  1727     because it will disappear altogether at some point.
  1728   - Users are strongly encouraged to write "0 < n" rather than
  1729     "n ~= 0". Theorems and proof tools have been modified towards this
  1730     `standard'.
  1731 
  1732 * HOL/Lists:
  1733   the function "set_of_list" has been renamed "set" (and its theorems too);
  1734   the function "nth" now takes its arguments in the reverse order and
  1735   has acquired the infix notation "!" as in "xs!n".
  1736 
  1737 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1738 
  1739 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1740   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1741 
  1742 * HOL/record: extensible records with schematic structural subtyping
  1743 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1744 still lacks various theorems and concrete record syntax;
  1745 
  1746 
  1747 *** HOLCF ***
  1748 
  1749 * removed "axioms" and "generated by" sections;
  1750 
  1751 * replaced "ops" section by extended "consts" section, which is capable of
  1752   handling the continuous function space "->" directly;
  1753 
  1754 * domain package:
  1755   . proves theorems immediately and stores them in the theory,
  1756   . creates hierachical name space,
  1757   . now uses normal mixfix annotations (instead of cinfix...),
  1758   . minor changes to some names and values (for consistency),
  1759   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1760   . separator between mutual domain defs: changed "," to "and",
  1761   . improved handling of sort constraints;  now they have to
  1762     appear on the left-hand side of the equations only;
  1763 
  1764 * fixed LAM <x,y,zs>.b syntax;
  1765 
  1766 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1767 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1768 
  1769 
  1770 *** FOL and ZF ***
  1771 
  1772 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1773   with `addloop' of the simplifier to faciliate case splitting in premises.
  1774 
  1775 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1776 in HOL, they strip ALL and --> from proved theorems;
  1777 
  1778 
  1779 
  1780 New in Isabelle94-8 (May 1997)
  1781 ------------------------------
  1782 
  1783 *** General Changes ***
  1784 
  1785 * new utilities to build / run / maintain Isabelle etc. (in parts
  1786 still somewhat experimental); old Makefiles etc. still functional;
  1787 
  1788 * new 'Isabelle System Manual';
  1789 
  1790 * INSTALL text, together with ./configure and ./build scripts;
  1791 
  1792 * reimplemented type inference for greater efficiency, better error
  1793 messages and clean internal interface;
  1794 
  1795 * prlim command for dealing with lots of subgoals (an easier way of
  1796 setting goals_limit);
  1797 
  1798 
  1799 *** Syntax ***
  1800 
  1801 * supports alternative (named) syntax tables (parser and pretty
  1802 printer); internal interface is provided by add_modesyntax(_i);
  1803 
  1804 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1805 be used in conjunction with the Isabelle symbol font; uses the
  1806 "symbols" syntax table;
  1807 
  1808 * added token_translation interface (may translate name tokens in
  1809 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1810 the current print_mode); IMPORTANT: user print translation functions
  1811 are responsible for marking newly introduced bounds
  1812 (Syntax.mark_boundT);
  1813 
  1814 * token translations for modes "xterm" and "xterm_color" that display
  1815 names in bold, underline etc. or colors (which requires a color
  1816 version of xterm);
  1817 
  1818 * infixes may now be declared with names independent of their syntax;
  1819 
  1820 * added typed_print_translation (like print_translation, but may
  1821 access type of constant);
  1822 
  1823 
  1824 *** Classical Reasoner ***
  1825 
  1826 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1827 some limitations.  Blast_tac...
  1828   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1829   + ignores elimination rules that don't have the correct format
  1830         (the conclusion MUST be a formula variable)
  1831   + ignores types, which can make HOL proofs fail
  1832   + rules must not require higher-order unification, e.g. apply_type in ZF
  1833     [message "Function Var's argument not a bound variable" relates to this]
  1834   + its proof strategy is more general but can actually be slower
  1835 
  1836 * substitution with equality assumptions no longer permutes other
  1837 assumptions;
  1838 
  1839 * minor changes in semantics of addafter (now called addaltern); renamed
  1840 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1841 (and access functions for it);
  1842 
  1843 * improved combination of classical reasoner and simplifier:
  1844   + functions for handling clasimpsets
  1845   + improvement of addss: now the simplifier is called _after_ the
  1846     safe steps.
  1847   + safe variant of addss called addSss: uses safe simplifications
  1848     _during_ the safe steps. It is more complete as it allows multiple
  1849     instantiations of unknowns (e.g. with slow_tac).
  1850 
  1851 *** Simplifier ***
  1852 
  1853 * added interface for simplification procedures (functions that
  1854 produce *proven* rewrite rules on the fly, depending on current
  1855 redex);
  1856 
  1857 * ordering on terms as parameter (used for ordered rewriting);
  1858 
  1859 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1860 
  1861 * the solver is now split into a safe and an unsafe part.
  1862 This should be invisible for the normal user, except that the
  1863 functions setsolver and addsolver have been renamed to setSolver and
  1864 addSolver; added safe_asm_full_simp_tac;
  1865 
  1866 
  1867 *** HOL ***
  1868 
  1869 * a generic induction tactic `induct_tac' which works for all datatypes and
  1870 also for type `nat';
  1871 
  1872 * a generic case distinction tactic `exhaust_tac' which works for all
  1873 datatypes and also for type `nat';
  1874 
  1875 * each datatype comes with a function `size';
  1876 
  1877 * patterns in case expressions allow tuple patterns as arguments to
  1878 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1879 
  1880 * primrec now also works with type nat;
  1881 
  1882 * recdef: a new declaration form, allows general recursive functions to be
  1883 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1884 
  1885 * the constant for negation has been renamed from "not" to "Not" to
  1886 harmonize with FOL, ZF, LK, etc.;
  1887 
  1888 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1889 infinite lists;
  1890 
  1891 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1892 
  1893 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1894 problems in commutative rings, using axiomatic type classes for + and *;
  1895 
  1896 * more examples in HOL/MiniML and HOL/Auth;
  1897 
  1898 * more default rewrite rules for quantifiers, union/intersection;
  1899 
  1900 * a new constant `arbitrary == @x.False';
  1901 
  1902 * HOLCF/IOA replaces old HOL/IOA;
  1903 
  1904 * HOLCF changes: derived all rules and arities
  1905   + axiomatic type classes instead of classes
  1906   + typedef instead of faking type definitions
  1907   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1908   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1909   + eliminated the types void, one, tr
  1910   + use unit lift and bool lift (with translations) instead of one and tr
  1911   + eliminated blift from Lift3.thy (use Def instead of blift)
  1912   all eliminated rules are derived as theorems --> no visible changes ;
  1913 
  1914 
  1915 *** ZF ***
  1916 
  1917 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1918 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1919 as ZF_cs addSIs [equalityI];
  1920 
  1921 
  1922 
  1923 New in Isabelle94-7 (November 96)
  1924 ---------------------------------
  1925 
  1926 * allowing negative levels (as offsets) in prlev and choplev;
  1927 
  1928 * super-linear speedup for large simplifications;
  1929 
  1930 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1931 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1932 FAIL); can suppress it using the command Delsimps (ex_simps @
  1933 all_simps); De Morgan laws are also now included, by default;
  1934 
  1935 * improved printing of ==>  :  ~:
  1936 
  1937 * new object-logic "Sequents" adds linear logic, while replacing LK
  1938 and Modal (thanks to Sara Kalvala);
  1939 
  1940 * HOL/Auth: correctness proofs for authentication protocols;
  1941 
  1942 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1943 examples on HOL/Auth);
  1944 
  1945 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1946 the rewriter and classical reasoner simultaneously;
  1947 
  1948 * function uresult no longer returns theorems in "standard" format;
  1949 regain previous version by: val uresult = standard o uresult;
  1950 
  1951 
  1952 
  1953 New in Isabelle94-6
  1954 -------------------
  1955 
  1956 * oracles -- these establish an interface between Isabelle and trusted
  1957 external reasoners, which may deliver results as theorems;
  1958 
  1959 * proof objects (in particular record all uses of oracles);
  1960 
  1961 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1962 
  1963 * "constdefs" section in theory files;
  1964 
  1965 * "primrec" section (HOL) no longer requires names;
  1966 
  1967 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1968 
  1969 
  1970 
  1971 New in Isabelle94-5
  1972 -------------------
  1973 
  1974 * reduced space requirements;
  1975 
  1976 * automatic HTML generation from theories;
  1977 
  1978 * theory files no longer require "..." (quotes) around most types;
  1979 
  1980 * new examples, including two proofs of the Church-Rosser theorem;
  1981 
  1982 * non-curried (1994) version of HOL is no longer distributed;
  1983 
  1984 
  1985 
  1986 New in Isabelle94-4
  1987 -------------------
  1988 
  1989 * greatly reduced space requirements;
  1990 
  1991 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1992 
  1993 * searchable theorem database (see the section "Retrieving theorems" on
  1994 page 8 of the Reference Manual);
  1995 
  1996 * new examples, including Grabczewski's monumental case study of the
  1997 Axiom of Choice;
  1998 
  1999 * The previous version of HOL renamed to Old_HOL;
  2000 
  2001 * The new version of HOL (previously called CHOL) uses a curried syntax
  2002 for functions.  Application looks like f a b instead of f(a,b);
  2003 
  2004 * Mutually recursive inductive definitions finally work in HOL;
  2005 
  2006 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2007 translates to the operator "split";
  2008 
  2009 
  2010 
  2011 New in Isabelle94-3
  2012 -------------------
  2013 
  2014 * new infix operator, addss, allowing the classical reasoner to
  2015 perform simplification at each step of its search.  Example:
  2016         fast_tac (cs addss ss)
  2017 
  2018 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2019 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2020 look like (a,b) instead of <a,b>;
  2021 
  2022 * PLEASE NOTE: CHOL will eventually replace HOL!
  2023 
  2024 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2025 It translates to the operator "split".  A new theory of integers is available;
  2026 
  2027 * In ZF, integer numerals now denote two's-complement binary integers.
  2028 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2029 
  2030 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2031 of the Axiom of Choice;
  2032 
  2033 
  2034 
  2035 New in Isabelle94-2
  2036 -------------------
  2037 
  2038 * Significantly faster resolution;
  2039 
  2040 * the different sections in a .thy file can now be mixed and repeated
  2041 freely;
  2042 
  2043 * Database of theorems for FOL, HOL and ZF.  New
  2044 commands including qed, qed_goal and bind_thm store theorems in the database.
  2045 
  2046 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2047 a given theory (thms_of), or find out what theory a theorem was proved in
  2048 (theory_of_thm);
  2049 
  2050 * Bugs fixed in the inductive definition and datatype packages;
  2051 
  2052 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2053 and HOL_dup_cs obsolete;
  2054 
  2055 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2056 have been removed;
  2057 
  2058 * Simpler definition of function space in ZF;
  2059 
  2060 * new results about cardinal and ordinal arithmetic in ZF;
  2061 
  2062 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2063 types;
  2064 
  2065 
  2066 $Id$